This patch adds support for loading a kexec on panic (kdump) kernel.
It has been tested with vmcore-dmesg on riscv64 QEMU on both an smp
and a non-smp system.
Signed-off-by: Li Zhengyu <lizhengyu3@xxxxxxxxxx>
---
arch/riscv/kernel/elf_kexec.c | 119 +++++++++++++++++++++++++++++++++-
1 file changed, 118 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c
index 2d442a849871..911d65d5a123 100644
--- a/arch/riscv/kernel/elf_kexec.c
+++ b/arch/riscv/kernel/elf_kexec.c
@@ -18,6 +18,8 @@
#include <linux/of.h>
#include <linux/libfdt.h>
#include <linux/types.h>
+#include <linux/memblock.h>
+#include <asm/setup.h>
static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
struct kexec_elf_info *elf_info, unsigned long old_pbase,
@@ -97,6 +99,79 @@ static int elf_find_pbase(struct kimage *image, unsigned long kernel_len,
return ret;
}
+static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
+{
+ unsigned int *nr_ranges = arg;
+
+ (*nr_ranges)++;
+ return 0;
+}
+
+static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
+{
+ struct crash_mem *cmem = arg;
+
+ cmem->ranges[cmem->nr_ranges].start = res->start;
+ cmem->ranges[cmem->nr_ranges].end = res->end;
+ cmem->nr_ranges++;
+
+ return 0;
+}
+
+static int prepare_elf_headers(void **addr, unsigned long *sz)
+{
+ struct crash_mem *cmem;
+ unsigned int nr_ranges;
+ int ret;
+
+ nr_ranges = 1; /* For exclusion of crashkernel region */
+ walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
+
+ cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
+ if (!cmem)
+ return -ENOMEM;
+
+ cmem->max_nr_ranges = nr_ranges;
+ cmem->nr_ranges = 0;
+ ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
+ if (ret)
+ goto out;
+
+ /* Exclude crashkernel region */
+ ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+ if (!ret)
+ ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
+
+out:
+ kfree(cmem);
+ return ret;
+}
+
+static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
+ unsigned long cmdline_len)
+{
+ int elfcorehdr_strlen;
+ char *cmdline_ptr;
+
+ cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
+ if (!cmdline_ptr)
+ return NULL;
+
+ elfcorehdr_strlen = sprintf(cmdline_ptr, "elfcorehdr=0x%lx ",
+ image->elf_load_addr);
+
+ if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) {
+ pr_err("Appending elfcorehdr=<addr> exceeds cmdline size\n");
+ kfree(cmdline_ptr);
+ return NULL;
+ }
+
+ memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len);
+ /* Ensure it's nul terminated */
+ cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0';
+ return cmdline_ptr;
+}
+
static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
unsigned long kernel_len, char *initrd,
unsigned long initrd_len, char *cmdline,
@@ -106,10 +181,12 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
unsigned long old_kernel_pbase = ULONG_MAX;
unsigned long new_kernel_pbase = 0UL;
unsigned long initrd_pbase = 0UL;
- void *fdt;
+ unsigned long headers_sz;
+ void *fdt, *headers;
struct elfhdr ehdr;
struct kexec_buf kbuf;
struct kexec_elf_info elf_info;
+ char *modified_cmdline = NULL;
ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
if (ret)
@@ -130,6 +207,45 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
kbuf.image = image;
kbuf.buf_min = new_kernel_pbase + kernel_len;
kbuf.buf_max = ULONG_MAX;
+
+ /* Add elfcorehdr */
+ if (image->type == KEXEC_TYPE_CRASH) {
+ ret = prepare_elf_headers(&headers, &headers_sz);
+ if (ret) {
+ pr_err("Preparing elf core header failed\n");
+ goto out;
+ }
+
+ kbuf.buffer = headers;
+ kbuf.bufsz = headers_sz;
+ kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+ kbuf.memsz = headers_sz;
+ kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
+ kbuf.top_down = true;
+
+ ret = kexec_add_buffer(&kbuf);
+ if (ret) {
+ vfree(headers);
+ goto out;
+ }
+ image->elf_headers = headers;
+ image->elf_load_addr = kbuf.mem;
+ image->elf_headers_sz = headers_sz;
+
+ pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
+
+ /* Setup cmdline for kdump kernel case */
+ modified_cmdline = setup_kdump_cmdline(image, cmdline,
+ cmdline_len);
+ if (!modified_cmdline) {
+ pr_err("Setting up cmdline for kdump kernel failed\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ cmdline = modified_cmdline;
+ }
+
/* Add the initrd to the image */
if (initrd != NULL) {
kbuf.buffer = initrd;
@@ -170,6 +286,7 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
out_free_fdt:
kvfree(fdt);
out:
+ kfree(modified_cmdline);
kexec_free_elf_info(&elf_info);
return ret ? ERR_PTR(ret) : NULL;
}
--
2.17.1
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